Inductive signal transfer device, useful for aviators&#39; helmets



June 11, 1968 c. A. CRAFTS ET AL. 3,387,606

INDUCTIVE SIGNAL TRANSFER DEVICE, USEFUL FOR AVIATORS' HELMETS FiledMarch 12, 1962 INVENTORJ CECIL A. cRAFrs MAI/YARD n. McFAAM/YE BY Ja E.Marne A TTORNEYS United States Patent 3,387,606 INDUCTIVE SIGNALTRANSFER DEVICE, USEFUL FOR AVIATORS HELMETS Cecil A. Crafts, Santa Ana,Maynard D. McFarlane,

Tustin, and John E. Mitchell, Costa Mesa, Calif.,

assignors to Robertshaw Controls Company, Richmond, Va., a corporationof Delaware Filed Mar. 12, 1962, Ser. No. 178,980 9 Claims. (Cl.128-141) This invention relates to inductive signal transfer devices andmore particularly to their use in combination with an oxygen supplyconnection to a mask or helmet in a unitary quick disconnect arrangementwhich avoids the use of metal to metal contacts.

Astronauts and pilots of military aircraft in the upper atmosphererequire a helmet or mask for the control of the oxygen or air supply tothe pilot and, at the same time, require connections which can bequickly made or broken in the event it becomes necessary for the pilotto be quickly separated from the craft. Similarly, a diver may require ahelmet with an oxygen supply and a communication system associatedtherewith which may be broken away from the helmet by a single unitaryquick disconnect device capable of instantaneous action. It haspreviously been known to combine with a quick disconnect arrangement foran air supply, a plurality of electrical plugs and sockets each makingconnection with one circuit in a helmet and with an external circuit. Anexample of a combined quick disconnect oxygen supply with electricalinterconnections between the helmet and external circuitry employingstandard jacks and receptacles as illustrated in the patent to R. E.Darling, No. 2,634,311. A disadvantage has been found to result in sucha structure from the exposed position of the metal contacts which aresubject to surface leakage under conditions of moisture condensation,salt spray and immersion. Under vibration the relatively heavy structureof the components on which the plug and jack are mounted may causeintermittent contact between the plug and jack with the result thatcommunication between the pilot and the remainder of the system isinterrupted or is given false or misleading signals. The rather largesize of such a structure is also a disadvantage.

It has also been proposed that detachable connections be made between apower supply and another circuit by way of an inductive coupling as inthe case of the patent to B. Easton, No. 2,483,815. This patent employsa transformer primary and secondary, one concentric Within the other inwhich it is possible to connect the parts of but one circuit. Suchsignal inductive transfer devices have not heretofor been applicable tothe use of several independent circuits combined within a single plug-inmember without the resultant intermixing or cross talk of the signals inthe several circuits. It has likewise not been previously possible tocombine a multi-circuit interconnection device employing inductivetransfer with a quick disconnect feature such as is essential in theinterconnection of the pilots helmet or mask with external circuitry andhis oxygen supply.

It is accordingly an object of this invention to provide an insulatedplug-in type of electrical signal transfer device for use in oxygensupply quick disconnect service.

A further object of the invention is to provide a combined quickdisconnect electrical connection for a plu- 3,387,606 Patented June 11,1968 rality of circuits and an oxygen supply quick disconnect connectionin one unitary assembly.

A further object is to provide an induction signal transfer device for aplurality of circuits assembled in a single plug-in unit having noexposed electrical contacts subject to corrosion or shorting byatmospheric moisture.

A still further object of the invention is to provide an inductivesignal transfer device for a plurality of circuits where cross talkbetween the circuits is eliminated.

In achieving these objects this invention utilizes paired transformercore elements in plug and receiver portions, one for each circuit to beestablished. Adjacent pairs of flux controlling cores are closely spacedbut disposed to avoid cross linking flux. Each core and winding isembedded in plastic or the like to present a fully insulated exterior.

Other objects and features of the invention will be understood as theinvention is explained by reference to the following drawings in which:

FIG. 1 is a schematic view of a quick disconnect oxygen supply hoseconnection combined with inductively coupled electrical connections forthe pilots communication system.

FIG. 2 is a schematic diagram of a portion of a plug and receptacle ofFIG. 1, illustrating in detail the circuit connection between earphones, microphones and external circuits, and

FIG. 3 illustrates an alternative form of a signal transfer device for aplurality of circuits, employing a plug and receptacle suitable forheadwear use in which cross talk between circuits is avoided by afurther arrangement of the respective cores of the signal transferdevices.

Referring now more particularly to FIG. 1 there is illustrated at 10 anoxygen supply hose connected to a supply (not shown) such as might becontained in the aircraft in which the pilot is operating. An oxygenoutlet to the mask or helmet of the pilot is indicated at 11 as atubular portion of the receiver portion of the quick disconnect fixture.The hose member 10 preferably terminates in a plug member 12 which maybe of rectangular form having plane surfaces at the upper and lowersides thereof as viewed in FIG. 1, suitable for close fitting insertionin a receiver 13 to which the hose member 10 is to be connected by wayof the plug member 12, thereby to provide a continuous oxygen supplyfrom 10 to 11. Details of such a quick disconnect feature in the oxygensupply for a helmet are disclosed in patent application Ser. No. 166,565filed Jan. 16, 1962, by John E. Mitchell and Lloyd L. Bissing, assignedto the common assignee with the present application. Since thesefeatures do not form a part of the present invention they will notfurther be described here except to note that an arrangement is providedwhich connects the two hose portions in airtight relationship towithstand the pressure of the oxygen system and at the same time toprovide means for instantaneously disconnecting the plug and receivermembers.

The copending application employs metal to metal contacts in the facesof the plug member 12 and the receiver member 13 adjacent thereto.According to the present invention an arrangement is provided forreplacing the metal to metal contacts with inductive signal transferarrangements employing transformer core halves 14 and 15, disposed onein the plug member and the other in the reltssv sos ceiver memberimmediately adjacent thereto when the plug member is seated within thereceiver member. At the opposite face of the plug member 12 is disposeda transformer core half 16 and immediately adjacent thereto is thecomplementary member 17 in the receiver member, each such core memberbeing wholly within the member and so positioned that when the quickdisconnect device is assembled the magnetic circuit between core members14 and 15 and between members 16 and 17 is substantially closed. Leadsl818 and 1919 correspond each to a circuit extending into the plugmember and connecting with opposite terminals of windings 21 and 22 onthe corresponding primary core members 14 or 16.

In order that the signal transfer apparatus thus far described shall becompletely free of atmospheric shorting or corrosition it is preferablethat the assembled core and winding shall be embedded or potted in aplastic block as at 23 and 24, preferably formed by casting. One coreand winding may be placed in the plug pocket 25 and another inreceptacle pocked 26 in a position to leave each of the core end 27lying immediately beneath the surface as the block is cast thereover. itwill be understood that such a construction permits the finishing of thesurface above the core ends 27 as may be required to cause a proper fitbetween the plug member 12 and the a receiver member 13.

As more fully disclosed in the copending patent application the plugmember is engaged Within the receiver member and firmly held in thatposition by means of a retaining hook on the receiver member as at 28and a retaining bail 29 attached to the plug member. When the bail ispassed over the hook and the plug 12 is pressed into the receiver member13 it may be locked into position by a lever 30 to establish theairtight connection desired and, at the same time, hold correspondingcore ends 27 in position adjacent each other, separated only by a thinsection of the plastic block respectively surrounding each such coremember.

In FIG. 2 there are shown portions of members 12 and 13 in section,respectively, with core members 14, 16. 15 and 17 in position tosubstantially complete magnetic circuits therebetween to permit signaltransfer by induction. Winding 21 is connected to ear phones 31 by wayof the leads 32 and winding 21' is connected to an external circuit byway of the leads 18. Similarly the winding 22 is connected to amicrophone 33 by Way of leads 34 and winding 22' is connected to theexternal circuitry by way of leads 19.

For some purposes it may be desirable to have a third communicationscircuit to the helmet of the aviator. A r

second microphone may be connected to a further receiver core 35 andthence to a corresponding core 36 on the plug. Winding 37 on the core 35extends to microphone 38 and corresponding leads and winding on the core36 extends to circuitry within the airplane.

Such a third signal transfer device might be used, for example, with asecond microphone or other device as at 38, which might connect to asecond signal output from the pilot, going by internal craft connectionsto a copilot. The microphone 33 might be of the dynamic type in which asound powered diaphragm and signal generator furnishes currentinductively coupling windings 22 and 22' thence extending to theaircraft communication system by means of leads 19. Either microphone 38or 33 might be of the carbon button type or of any other constructionemploying a small battery to provide a current which is modulated by theaction of the microphone in order to provide a more adequate signal tobe coupled to the external communication system.

Since two magnetic circuits in closely spaced relation have a tendencyto interact under conditions of varying excitation, as incommunications, precautions are required to minimize the flux linkagefrom one transformer core to another. Considering the plug member 12 thecontained cores 14 and 16 are oppositely disposed to minimize fluxthcrebetween both by separation of pole pieces 27 and by orientation. Ina third closely spaced transformer the cores 35 and 36 may be disposedat right angles to the cores 14 and 15, or to 16 and 17 such that anyleakage flux is at right angles rather than parallel to the corestructure which might otherwise gather a portion thereof to induce crosscoupled signals.

Such an embodiment of the invention as has previously been described isparticularly adapted for use with a helmet-mounted oxygen supplyconnection of the quick disconnect type. but is not so limited in itsapplication. This arrangement may be employed in a divers helmet, abathysphere, or in any other similar arrangement in which it isnecessary to pass signals through an outer wall into an inner containerwithout the use of metal to metal contacts such as could be shorted byimmersion in water or by atmospheric moisture conditions.

One arrangement might include a divers or radiation monitors helmet towhich a connection must be made after the helmet is placed on thewearers head but which is quickly removable for washdown or in order togive mobiiity to the wearer, yet making possible the interconnection ofthe circuitry to and from his communication system without the use ofexposed contacts of any type. A cable 41 for this purpose might includea number of signal leads all enclosed within a waterproof rubber orplastic covering which connects to a plug member 42 by means of afairlead arrangement 43 protecting the cable against chafing or breakingat the connection point.

Plug member 42 in this version may be of cylindrical form in whichcorresponding core halves as at 14 and 16 of FIG. 2 are employed eachwith its winding thereon connecting to the leads within the cable 41.Such core members are disposed within the plug member in a position toexactly match the position of the corresponding core halves 15 and 17disposed within the outer Walls or lateral projections of the receiverand socket member 48, generally in the manner illustrated in FIG. 2,except that orientation is now required between the cylindrical plug andreceptacle members so that the corresponding core halves will beoppositely disposed for maximum transfer of signal.

Such a connector may also conveniently employ a third core 44 like core35 but disposed in the end of the plug member to cooperate with asimilar core 44 in the end of the socket member for the transfer of athird set of signals.

Placing the plane of cores 35 and 36 at right angles to nearby cores 14and 15 has been described as a necessary measure to minimize cross talkbetween circuits. In the arrangement shown in FIG. 3 the break in themagnetic circuit for core 44 is at right angles to the plane of thebreak for the core 14 or 16, and leakage flux paths of the respectivecores are at right angles thereby to prevent any substantial degree offlux linkage between the third and the first or second transfer devices.

The plug member 42 is preferably supplied with a key portion 46 alongone face thereof which fits within a slot 47 in the corresponding faceof the receptable member 48 such that when the two are placed inkey-oriented operative position this position is maintained withcertarnty and exactitude. The socket member is preferably attached to ahelmet or enclosure wall at 49 by means of attached nipple 51, collar 52and nut 53. Internal connections pass from the socket member through ahole 54 in wall 49 to leave an airtight enclosure through which signalspass without use of exposed metal electrical inserts or contacts.

It is desirable to maintain a close friction fit between the plug andsocket members of FIG. 3, but not to rely exclusively upon friction toprevent relative axial motion. Spring clips 55 and 56 are appropriatelysecured to the socket member along two or more opposed sides thereof bymeans of retaining ring 57 and/or slots according to the method ofmanufacture most convenient. Clips 55 and 56 have turned in portions 53arranged to overlie the outer end of the plug member when in place andretain it in that position, and have sloped portions 59 adapted to rideover the plug as it is inserted.

While the invention has been described in connection with particularembodiments it will be understood that other embodiments and equivalentsare contemplated within the scope of the appended claims.

What is claimed is:

1. A signal transfer device for quick disconnect service interconnectinga plurality of separated circuits,

a first transformer having a secondary core member and winding entirelyimbedded within a plastic receptacle wall,

a primary core and winding entirely imbedded in a plastic plug unitadapted to be fitted within said receptacle,

said plug and receptacle units being keyed for engagement inpredetermined alignment,

said core members being substantially of C-form and of size anddisposition within said plug and receptacle units, when aligned, tosubstantially complete a high permeability magnetic path through saidprimary and secondary core members,

a second transformer having primary and secondary core members each witha winding thereon entirely imbedded within receptacle and plug units,respectively, said core members being oriented at least 90 from the coremembers of the first transformers for reduction of magneticintercoupling therebetween, and

signal transmit-receive means connected to said windings of said firstand second transformers for the conveying of separate signalsthereth-rough in a plurality of circuits.

2. In a quick disconnect fixture for unitary oxygen hose andcommunication connections to headgear the combination of,

an oxygen supply line terminating in a plug member,

an oxygen receiver member on said headgear,

quick disconnect means connecting said plug and receiver members influid tight relation,

a first signal transfer means including matched transformer coreportions in juxtaposition one in said plug member and one in saidreceiver member,

sadi core portions being substantially of semicircular shape, eachhaving thereon an energizing winding, one to generate when electricallyenergized flux variations through both said portions and the other togenerate voltage signals by induction in response to said fiuxvariations,

a second signal transfer means generally like the first and includingtransformer core portions and windings being disposed with ends of saidcore portions of said plug member terminating in directions separatedsubstantially at least 90,

impregnating means covering said core and windings of each signaltransfer means and extending to form predetermined spacing between saidcore portions of each said transfer means,

and key means orienting and retaining said matched core portions in saidfixed juxtapositional relation.

3. In a helmet for supplying oxygen and communications to an aviator,

oxygen hose supply means including a termination for connection to saidhelmet,

receiver means detachably holding said termination in fluid tightrelation to said helmet,

a plug member of rectangular section enclosing said termination,

a receiver member of dimensions to enclose laterally said plug member infixed closely spaced relationship,

a pair of split transformer core portions in said plug member havingends thereof disposed each immediately beneath a lateral surface of saidplug member,

a pair of complementary core portions one for each prior said pair :andhaving ends thereof disposed each within an inner face of said receivermember in position for substantially completing in each case a trans-:former core when in said fixed relationship,

signal transfer windings on each said core portion,

means insulating the exterior surface of said plug and receiver membersto prevent sparking during disconnection thereof in the presence ofoxygen,

and signal generating and utilization means connected respectively tosaid windings completing signal transfer means to and from said helmet.

4. A signal transfer device for quick disconnect service comprising,

a cylindrical plug member,

a cylindrical receptacle member dimensioned to receive said plug memberin fitted relationship,

key means on each said member cooperating to retain orientationtherebetween when said plug member is within said receptacle member,

a first split circular magnetic core, half within said plug member andhalf within said receptacle member being disposed when in saidorientation to substantially complete a magnetic path between saidhalves,

a second split core disposed as the first to complete a similar magneticpat-h and being :at opposite sides of said plug and receptacle membersfrom first said core for minimizing flux linkage therebetween,

a third split core dispose-d half within said plug at an inner endthereof and half within said receptacle member with the split core endsin respective juxtaposition when in said orientation,

and induction windings on each core half for transferring signals to andfrom said plug member and said receptacle member in three magneticallyand electrically separate circuits.

5. The combination of claim 4 wherein each said core and winding thereonis enclosed within a plastic pocket in one said member.

6. A signal transfer assembly for quick disconnect service for aplurality of simultaneous signals without exposed intervening contactscomprising,

a cylindrical plastic plug member including therein a plurality of splitmagnetic core members of C shape each having a pair of ends terminatingimmediately beneath one surface of said plug member, the respectivemembers being disposed in opposed relation for minimizing magneticlinkage therebetween,

a cylindrical plastic receptacle member having a similar plurality ofsplit core members complementary to first said members and arranged withcorresponding core ends in juxtaposition to said ends, respectively, insaid plug member, when the plug member is seated in fixed orientationtherein,

primary and secondary windings on each pair of juxtaposed core membersfor inductively transferring separate signals in each said pair ofwindings,

and means connecting signal transducer means to the respective primaryand secondary windings for each said pair of core members.

7. An assembly according to claim 6 wherein two said cores of the plugmember are at sides of the cylindrical plug member not substantiallyless than apart.

8. An assembly according to claim 6 wherein one said core memberterminates within an inner end of said plug member and at least one saidcore member terminates within and at a lateral side of said plug member.

9. An assembly according to claim 6 wherein three said core members haveterminations oriented at least 90 one from another.

(References on following page) References Cited UNITED STATES PATENTSNeighbors 333-78 Rust 333-78 Stanko 175-361 Beers 33378 Easton 175356Meakin 333- 78 Barton 933* 78 Da rling 33916 Boothe 333-78 Mechert 33916Cushman et a1. 333-78 Fri-berg 333-78 Mitchell et a1 339-16 HERMAN KARLSAALBACH, Primaly Examiner. ELI LIEBERMAN, Examiner. Darling 173-326 10C. BARAFF. Assistant Examiner.

1. A SIGNAL TRANSFER DEVICE FOR QUICK DISCONNECT SERVICE INTERCONNECTINGA PLURALITY OF SEPARATED CIRCUITS, A FIRST TRANSFORMER HAVING ASECONDARY CORE MEMBER AND WINDING ENTIRELY IMBEDDED WITHIN A PLASTICRECEPTACLE WALL, A PRIMARY CORE AND WINDING ENTIRELY IMBEDDED IN APLASTIC PLUG UNIT ADAPTED TO BE FITTED WITHIN SAID RECEPTACLE, SAID PLUGAND RECEPTACLE UNITS BEING KEYED FOR ENGAGEMENT IN PREDETERMINEDALIGNMENT, SAID CORE MEMBERS BEING SUBSTANTIALLY OF C-FORM AND OF SIZEAND DISPOSITION WITHIN SAID PLUG AND RECEPTACLE UNITS, WHEN ALIGNED, TOSUBSTANTIALLY COMPLETE A HIGH PERMEABILITY MAGNETIC PATH THROUGH SAIDPRIMARY AND SECONDARY CORE MEMBERS, A SECOND TRANSFORMER HAVING PRIMARYAND SECONDARY CORE MEMBERS EACH WITH A WINDING THEREON ENTIRELY IMBEDDEDWITHIN RECEPTACLE AND PLUG UNITS, RESPECTIVELY, SAID CORE MEMBERS BEINGORIENTED AT LEAST 90* FROM THE CORE MEMBERS OF THE FIRST TRANSFORMERSFOR REDUCTION OF MAGNETIC INTERCOUPLING THEREBETWEEN, AND SIGNALTRANSMIT-RECEIVE MEANS CONNECTED TO SAID WINDINGS OF SAID FIRST ANDSECOND TRANSFORMERS FOR THE CONVEYING OF SEPARATE SIGNALS THERETHROUGHIN A PLURALITY OF CIRCUITS.